Composite materials generally refer to substances that have been engineered from two or more constituent materials with significantly different sets of properties. One of the constituent materials may be a substrate that exists in a fluid-like, viscous form until cured to a hardened state, such as an epoxy adhesive. To enhance particular characteristics of the cured substrate, one or more other constituent materials may be added. These constituent materials may remain separate and distinct from the substrate while in fluid form. When cured, the resulting composite material may have properties in which the constituent materials act in some kind of cooperative fashion to cause the composite material to have advantageous overall properties.